The word ‘third’ can function as different parts of speech depending on its use in a sentence.
1. **Adjective**: When ‘third’ describes the position of something in a sequence, it acts as an adjective. For example, in the sentence, ‘She finished in third place,’ ‘third’ modifies the noun ‘place’ and specifies the position.
2. **Noun**: ‘Third’ can also be used as a noun, particularly when referring to the third item in a series. For instance, in the phrase ‘The third of the group is the best,’ ‘third’ is a noun indicating which individual is being discussed.
In summary, ‘third’ is primarily used as an adjective and a noun, depending on its context in a sentence.